Wild type D-serine deaminase (Dsdase) synthesis in Escherichia coli K12 is controlled by induction and catabolite repression, both acting at the level of transcription. The induction control appears to be strictly postive. We propose to develop a workable cell-free system for Dsdase synthesis in order to test our theories on the mechanism of action of the intermediates involved in Dsdase regulation and the nature of their site(s) of action, and to isolate and characterize the product of the Dsdase regulatory gene.